In organic synthesis, in particular multistep synthesis, the purification of the products obtained can present more problems than the synthesis itself. This is particularly true in the case of peptide synthesis, a synthesis which systematically uses protective groups which can also play supplementary roles.
Thus, the need to protect, or activate, a certain function in amino acids has been used for carrying out biphasic peptide syntheses in order to facilitate the purification steps. Implicit in these techniques, such as the Merrifield technique (J. Amer. Chem. Soc., 108, 5242 (1986)), however, is the problem of purification of the synthesized peptides which has not been completely resolved. One of the most elegant solutions to this problem would be to modify the peptide, or any other molecule requiring protection, by binding it to a solid in a manner which is physically reversible, both in the course of working up and purification. To date no protective group has been disclosed as being capable of exercising such a property.
It is for this reason that one of the main aims of the present invention is to provide a protective group corresponding to the above criteria.